Onko Lamantinissa siis airot vai mikä tuosta törröttää?
Ilmeisesti ne ovat HF-alueen piiska-antenneja (HF whip antenna).
Andy Burnsin vastaus Quorassa:
They’re HF whip antennas. They’re on pivoting mounts and they’re cranked down for flight operations.
Answer (1 of 18): They’re HF whip antennas. They’re on pivoting mounts and they’re cranked down for flight operations.
www.quora.com
Baluncoren vastauksessa #10 Physicsforumsilla selostetaan noiden antennien käyttöä hieman laajemmin. Boldatussa lainauksessa mainitaan, että antennit ovat vaaka-asennossa aina lentotoiminnan aikaan sekä yleensäkin avomerellä ja nostetaan ylösasentoon vain satamissa, eikä niillä ole mitään putoamisenestofunktiota.
Mar 10, 2021 #10 Baluncore
The receive antennas are used in pairs for spatial diversity reception, one on each side of the flight deck. That is why they can be spaced closer together along the edge of the flight deck than would be the case for transmit antennas.
The transmit elements are not used in pairs. Transmission is from the individual more isolated whip elements, beyond the far end of the receive array, or at the other end of the vessel.
The elements only look like a vertical whip array while visiting port, when they are manually stowed in the vertical position. They are lowered into the horizontal operating position on return to sea. They are never vertical during flight operations.
See; Title: HF Receiving Antenna Arrangement on Flight-Deck Edge of Aircraft Carriers. Performances of Antennas in Different Locations and Paired Combinations are Compared. [Full text is not available]. Abstract
“Five possible sites were studied for placement of 2-30 MHz twin-whip antennas on the deck edge of ships of the CVA 59 to CVAN 68 types. … It was found that siting of the antennas did not appreciably affect their performance, provided they were more than quarter wavelength at 2 MHz, approximately equal to 125 feet from the forward and after ends of the flight deck and from the island. In pairing the antennas to achieve space diversity, the most important factor is the distance between them, which should be at least 200 feet.” https://apps.dtic.mil/sti/citations/AD0888366
Anyone serve on an aircraft carrier or in the know about them?
“I served as an electronics tech onboard the USS Nimitz for three years and those were my babies. Those are two piece 35 foot HF whip antenna. They are in the down position during flight operation (and generally when underway) to keep jet wings safe. They are manually lifted when in close confines. They have nothing to do with HFDF or fall arrest.”
Looking at a model of the HMS Ark Royal I found myself intrigued by the prominent 'poles' lining the flight deck. Some investigation on Google reveals that they can apparently be lowered to lay
engineering.stackexchange.com
Source
https://www.physicsforums.com/threa...-on-the-new-chinese-aircraft-carrier.1000602/
Myös Pohjanmaa-luokan havainnekuvissa näkyy pitkiä piiska-antenneja:
Vielä "ANTENNA CATALOG Volume III SHIP ANTENNAS" vuodelta 1960. Whip antenna esitelty sivulla 14.
